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Tuesday, April 22, 2014

SpaceX Brings a Booster Safely Back to Earth

As reported by MIT Technology Review: Space Exploration Technologies, or SpaceX,
took a step toward making spaceflight less expensive by reusing its
rocket boosters during a mission on Friday to the International Space
Station. The Falcon 9 rocket used for the mission, dubbed Commercial
Resupply-3, or CRS-3, was the first to fly with landing legs, and was
the first to successfully perform a controlled ocean splashdown.The launch of the third official cargo delivery mission by SpaceX to
the station had been delayed from last month and again from Monday due
to technical problems.The rocket, carrying a Dragon space capsule loaded with 3,500 pounds of supplies for the space station, lifted off at just after 3:25 p.m.
EST. The Dragon spacecraft reached the precise orbit needed to
rendezvous with the space station on Sunday.The mission was the first successful test of a new capability for the
first stage of the Falcon 9: the ability to descend to a soft touchdown
after delivering its payload to orbit. Conventional rocket boosters
fall back to Earth after expending their fuel, reentering the atmosphere
fast enough to disintegrate in the heat caused by friction with the
air. This adds greatly to launch costs, which can top $200 million per
launch, since a new rocket has to be built for each flight (see “SpaceX to Launch World’s First Reusable Rocket”).SpaceX is already the lowest-cost provider of launch services to the
U.S. government and the commercial satellite industry, with flights
costing less than $100 million. The company hopes to drop costs even
further with reusable rockets. SpaceX has been testing a Falcon 9 first
stage in low-altitude hops at its McGregor, Texas, rocket development
and testing center. The company posted a video of a test flight that took place last week with the same type of landing legs used on Friday’s orbital flight.A camera on the second stage of the rocket captured live video of the
nine SpaceX-built Merlin engines firing on the first stage of the
rocket, with the plume of flame and smoke gradually expanding as the air
around the vehicle thinned. At about 50 miles in altitude, and
traveling at about 10 times the speed of sound some 35 miles off the
Florida coast, the first-stage engines cut off as planned. As the first
stage dropped away, the single Merlin engine in the second stage fired
to propel the Dragon craft the rest of the way into orbit. Another
camera view showed the Dragon moving away from the second stage into
space with the Earth as a backdrop.Meanwhile, a data link with the first stage confirmed that three of
the nine engines on the first stage had fired as planned to slow the
booster’s reëntry into the atmosphere. The plan then called for a single
engine to restart at lower altitude over the Atlantic Ocean to enable a
gentle splashdown. The second stage of the rocket was not designed to
be recovered.

Fly away: After separating from a SpaceX Falcon rocket, the Dragon capsule heads off toward the International Space Station.

At a press conference about an hour and a half after the
launch, SpaceX CEO Elon Musk confirmed that the initial data from the
first-stage booster looked good. The booster had slowed to just over the
speed of sound and had descended to about five miles, or about the
altitude of a commercial airliner, before the terrestrial tracking
station lost contact.The latest data showed that the vehicle was not rolling. During the
first attempt of a Falcon 9 first stage to safely splash down following
an orbital flight, in November, the rocket spun out of control. Along
with the addition of landing legs, the booster used for Friday’s flight
included more powerful thrusters for countering the booster’s rolling
motion.Even so, Musk was not initially confident that the booster had landed softly on the water because of high waves.“I think it’s unlikely that the rocket was able to splash down
successfully,” he said during the post-flight press conference. At the
time of the conference, he and his engineers were awaiting data from an
airplane tracking the booster near the planned splashdown location, some
400 to 500 miles from Cape Canaveral. Boats that were to retrieve the
booster were not able to approach the splashdown site because of the
waves, which topped 15 to 20 feet.However, Musk reported via Twitter about two hours after the press
conference that the booster had indeed landed safely. “Data upload from
tracking plane shows landing in Atlantic was good!” he tweeted. “Flight
computers continued transmitting for 8 seconds after reaching the water.
Stopped when booster went horizontal.” At last report, the crews of
several boats were attempting to retrieve the booster.SpaceX engineers are working toward the day when a Falcon 9 first
stage will touch down on land. The company will attempt a touchdown on
land after it demonstrates further precision splashdowns. The next big
milestone following the successful recovery of a booster will be to
reuse one, which could happen as early as next near. The company’s goal
is not only to recover and reuse boosters, but to do so economically.“The reuse must be both rapid and complete,” said Musk in the press
conference, “like an aircraft or a car or something like that. If you
have to disassemble and reassemble a car and change a bunch of parts in
between driving it, it would make it quite expensive. So it’s true that
we don’t just have to recover it, we have to show that it can be reflown
quickly and easily with the only thing changing being reloading
propellant.”

The Dragon that launched on Friday’s flight reached Space Station and
was grappled by the station’s robotic arm on Sunday morning. It was
then installed at the Earth-facing port on the station’s Harmony module.This was the fifth flight of a Dragon spacecraft. SpaceX has a
contract with NASA for nine more cargo deliveries to the International
Space Station. The company plans 10 more flights this year, including
commercial satellite launches, each one of which will offer an
opportunity to recover a booster.

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I have more than 25 years of experience in development, design, and mobile communications products and technology. I also enjoy skiing, hiking, scuba, tennis, reading, traveling, foreign languages, and painting. I'm an active member of the National Ski Patrol (NSP) and volunteer my time at either Loveland Ski resort, or Ski Cooper.